Environmental Engineering Reference
In-Depth Information
abrupt change in loop currents, resulting in impulsive inductor volt-
ages. The impulsive currents (voltages) re-distribute charge (flux) in
the networks at switching instants instantaneously. As a result, the
value of the network variables of these circuits immediately before
switching differs from that immediately after switching, leading to
inconsistent initial conditions, which can not be handled by conven-
tional numerical integration methods.
High output noise power-
for circuits with externally clocked switches,
the clocking frequency is usually much higher than the frequency of
input signals, mainly due to the need to avoid spectrum overlap-
ping of the sampled signals (Nyquist theorem). The equivalent noise
bandwidth of these circuits, however, is usually several orders of mag-
nitude higher than the sampling frequency. The under-sampling of
the broad-band noise sources in these circuits, such as shot noise and
thermal noise that are white in nature, gives rise to the fold-over ef-
fect where the output noise power of these circuits is not determined
by the in-band noise power of the noise sources, but rather dominated
by the noise power of the sideband components of these white noise
sources that is folded over to the baseband. As a result, mixed-mode
switching circuits exhibit a significantly high level of output noise
power in the baseband.
Search WWH ::
Custom Search